Intraoperative Topically-Applied Non-Implantable Rapid Release Patch

ABSTRACT

A device for delivery of a therapeutic agent to a surgical cavity, including: a porous, mucoadhesive, freeze-dried polymeric matrix having first and second opposed surfaces, the matrix formed by a composition including chitosan; a plurality of particles embedded within the matrix, the particles containing the therapeutic agent and having a coating around the therapeutic agent, the coating including chitosan. The first surface of the matrix is configured to be applied to the surgical cavity; the device releases the particles through the first surface; the device is also sterilized and provides release of approximately 20% to 100% of the therapeutic agent within 20 minutes of application to the surgical cavity.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No.15/970,513, filed on May 3, 2018, issuing Nov. 19, 2019, as U.S. Pat.No. 10,478,403, which claims the benefit of U.S. provisional applicationNo. 62/500,824, filed on May 3, 2017. Both of these applications arehereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention is in the field of formulations for targeted rapiddelivery of agents intraoperatively to surgical cavities of organs andtissue.

BACKGROUND

Survival rates and quality of life of cancer patients can besignificantly improved if recurrence and further metastasis can bereduced or eliminated. When tumors are discovered, surgery is often usedto resect and eliminate primary and secondary tumors. When surgery isutilized, however, the risk of metastasis and recurrent can actuallyincrease and remains high, because the surgical cavity and surgicalprocedure results in an environment which promotes the spread ofremaining cancer cells. For example, by cutting into human tissue,natural tissue formations and barriers are disrupted and the bloodstreamcan become exposed, while simultaneously, healthy and cancerous cellsbreak apart or otherwise become freed during surgery. In many cases,this combination results in cancerous cells becoming freed and exposedto the bloodstream, and promotes eventual metastasis to additionalregions, or recurrence locally/regionally.

Cancer cells are able to ‘break away” from their original tumor site andtravel through the bloodstream or lymphatic system to new locations,where additional cancers will start to proliferate [1, 2]. Most cancercells that break free from the original tumor are carried in the bloodor lymph until they get trapped in the next “downstream” organ or set oflymph nodes. This explains why breast cancer often spreads to underarmlymph nodes, but rarely to lymph nodes in the groin [1]. The liver is acommon site of spread for cancer cells that start in the colon becauseblood from the intestines flows into the liver [1].

When a tumor remains intact, cancer cells sometimes metastasize toadditional locations through the series of the following steps: (1)invading nearby local tissue, (2) moving through the walls of nearbylymph nodes or blood vessels, (3) traveling through the lymphatic systemand/or bloodstream to other parts of the body, (4) stopping in smallblood vessels at a distant location, invading the blood vessels, andmoving into surrounding tissue, (5) growing in the tissue, forming largetumors [2]. Presently, few treatment options are available in responseto metastatic tumors. These include additional surgery, systemicchemotherapy and radiation. However, any treatment for tumor recurrencepost the second surgery will be for palliative purposes. On rareoccasions, intraoperative radiation therapy (IORT) and intraoperativeheated intraperitoneal chemotherapy (HIPEC) are used to deliver highlyfocused and intense therapy to reduce the chance of metastasis. Whileincrease in efficacy has been shown, these intraoperative treatmentsremain very uncommon due to significant cost burden, large size andcomplexity in operation. There are also considerable risks and drawbacksassociated with their use, as well as lack of widespread availability.In addition, these treatment options are limited in their targeting oftumor tissue, which hinders their efficacy and can lead to recurrenceand further metastasis. This is due to the micro-metastatic riskassociated with surgery.

As mentioned above, cancer cells can often “break away” from the primarytumor site and travel through the bloodstream to additional regions,forming new tumors. This risk is drastically amplified by the use ofsurgery, which slices into tissue and disrupts tumor and healthy tissue.Many cells are broken up and freed during surgery including cancercells, and are simultaneously exposed to the bloodstream, which canfacilitate the spread of malignant tumor cells through the bloodstreamto additional sites [3].

Currently, post-surgery radiation and chemotherapy (approximately 30days post-surgery for wound healing) is utilized; however, tumorrecurrence and death still remain a major problem. The need to destroythe potential micrometastatic cells even prior to wound healing stepspost-surgery is a novel approach that can reduce the tumor recurrencepost-surgery [8].

It has been shown that there are important parallels between woundhealing and metastasis, and cancer cells may rely on these pathways tosurvive and metastasize. Primary tumor removal activates wound healingpathways as a result of the surgical trauma, the removal of the primarytumor, and the seeding of cancer cells into the circulation. Thesepathways are activated immediately after surgery, with the peak increasein the proliferation of residual cancer cells occurring within 24-72hours after primary tumor removal. Allowing wound healing to occurbefore initiating therapy may be facilitating metastatic spread of thecancer and compromising the subsequent effectiveness of that therapy.

Intra-operative radiation therapy (IORT) and systemic intravenouschemotherapy are treatment options which can be utilized to reduce oreliminate metastatic cancer. They are utilized after a tumor is removedto eliminate remaining tumor cells. These aforementioned treatmentoptions, however, are limited in their ability to target tumor cells,carry substantial risks and side effects, and are in many cases highlyexpensive and not available to significant numbers of patients. IORT isa treatment option which directs a high concentration of radiation to asurgical cavity following the resection of a cancerous tumor. IORT iscommonly used in breast cancer patients, for example, following surgicaltumor resection [9, 10]. A metal disk is placed behind the targetedbreast tissue to spare the underlying tissue, and high concentrations ofradiation are directed to the surgical cavity [10]. IORT has also shownpromising results when combined with pre-operative external beamirradiation plus chemotherapy and tumor resection for high-risk patientswith locally advanced primary or locally recurrent colorectal cancer.IORT is not commonly used to treat metastatic colorectal cancer.

Despite some advantages of IORT, there are significant drawbacks to thetherapy, the first of which relates to the cost and commercialavailability of the treatment option. The NOVAC 7 (Sordina IORT Tech,Italy) is an example machine used to administer IORT. The machine isexpensive, requires skilled personnel to operate and maintain, and isnot readily available. It is a large complex machine that weighsapproximately 790 kg [11]. In addition, IORT is a standard procedurewhich is not suitable for every patient. Surprisingly, only 25% ofpatients are deemed to be an appropriate fit for IORT [6]. IORT addsapproximately 30 minutes onto the treatment procedure, and additionalradiation following tumor resection and IORT can be necessary [10].

Heated intraperitoneal chemotherapy (HIPEC) is another procedure whichis commonly used to reduce or eliminate tumors from organs and surfaceswithin the abdomen. Like IORT, cytoreductive surgery is performed priorto HIPEC treatment [12]. HIPEC is used within the abdomen and pelvis.HIPEC is utilized for metastatic cancers on tissues including thestomach, small intestine, colon, liver, spleen, pancreas, uterus,rectum, omentum, ovaries and other peritoneal surfaces [12]. The processinvolves cytoreduction followed by the placement of tubes andtemperature probes into the abdominal cavity [12, 13]. The skin issutured closed, and the reverse sides of the tubes are attached to amachine which regulates temperature and flow rate. The tubes introduce asaline solution within the abdominal cavity, followed by draining andflooding of the abdominal cavity with a heated chemotherapy solution[12, 13]. The solution is heated to approximately 42-43 degrees Celsius.The abdomen is shaken to allow homogenous distribution of the solution,and the solution is subsequently drained. The abdomen is again washedwith saline solution. The abdomen is then re-opened, the tubes areremoved, and the abdomen is stapled closed. The entire procedureincluding surgery can take 6-14 hours, and the HIPEC can take in excessof 90 minutes to administer [12, 13]. Patients remain in the hospitalfor 10-12 days following the procedure.

The described HIPEC treatment option, while increasing in use, carriessignificant drawbacks, including debilitating side effects, lengthytreatment time, and poor targeting. Similarly to IORT, the machine usedto administer and regulate the HIPEC solutions is expensive, requireshighly specialized personnel, and is, as a consequence, not commerciallyavailable to all patients. In 2013, only 27 states in the US had atleast one expert able to administer HIPEC and, as a result, thoseseeking HIPEC treatment are typically “highly motivated, younger,healthier and wealthier” individuals [14]. In addition, side effects canbe severe, including bleeding, infection, and even death during orshortly following treatment [14]. Blood clots can also form in the legsof patients and travel to parts of the body such as the lungs. Thedevelopment of an enterocutaneous fistula (opening between theintestines and abdominal skin) or anastomotic leak (a leak that mayoccur when sections of the intestines are surgically reconnected) canalso occur [14]. In addition, fatigue can plague patients for 2-3 monthsfollowing the procedure, and nutritional intake can be reduced, howeverthis side effect is in part caused by the surgical procedures as well.Overall, 1% of people die as a result of the treatment and 12%experience serious post-operative problems [14]. In addition, thechemotherapy agent administered in solution form is “poorly absorbed bythe underlying tissue” [4] and is only somewhat targeted to the largeintraperitoneal cavity.

There is a desperate need for a safe intraoperative chemotherapy tominimize the risk of tumor cell implantation and metastasis duringcancer surgeries such as head and neck cancers [8]. The treatment needsto be inexpensive and simple to administer to enable its widespreadavailability and adoption.

SUMMARY OF THE EMBODIMENTS

In one set of representative embodiments, there is provided a device fordelivery of a therapeutic agent to a surgical cavity, the devicecomprising: a porous, mucoadhesive, freeze-dried polymeric matrix havingfirst and second opposed surfaces, the matrix formed by a compositioncomprising chitosan; a plurality of particles embedded within the matrixso as to be directly surrounded by, and in contact with, the matrix, theparticles containing the therapeutic agent and having a coating aroundthe therapeutic agent, the coating comprising chitosan so as to providecontrolled release of the therapeutic agent from the particles throughthe first opposed surface of the matrix; and an additive selected fromthe group consisting of a hydration promoter, a particle adhesioninhibitor, a particle aggregation inhibitor, and combinations thereof.The first surface of the matrix is configured to be applied to thesurgical cavity; the device is configured to provide release of theparticles through the first surface; the device is also sterilized andprovides release of approximately 20% to 100% of the therapeutic agentwithin 20 minutes of application to the surgical cavity.

The hydration promoter may be selected from the group consisting ofethylene glycol, propylene glycol, beta-propylene glycol, glycerol, andcombinations thereof. The particle adhesion inhibitor may be a non-ionicpolymer, for example hydroxypropyl methylcellulose. The particleaggregation inhibitor may be selected from the group consisting ofmonosaccharides, disaccharides, sugar alcohols, chlorinatedmonosaccharides, chlorinated disaccharides, and combinations thereof.The particles may further include sodium tripolyphosphate. The devicemay also include a free quantity of the therapeutic agent, embeddeddirectly in the matrix, and not otherwise coated with chitosan, whereinthe free quantity of the therapeutic agent constitutes between 20-80% ofa total quantity of therapeutic agent in the device. The device mayfurther comprise a backing layer disposed on the second surface, whereinthe backing layer prevents significant loss of payload components in thedevice from diffusion through the second surface, and optionallyprotects the device from an environment. The backing layer may include amaterial selected from the group consisting of a polyacrylate adhesive,a non-woven polyester fabric backing, or combinations thereof. Theaverage diameter of the particles may be from about 60 nm to about 2000nm. In some embodiments, the therapeutic agent may be a chemotherapeuticpharmaceutical, for example one selected from the group consisting ofplatinum-based chemotherapeutics, 5-flurouracil, and combinationsthereof. The therapeutic agent may also be an agent selected from thegroup consisting of anti-infective, anti-bacterial, or anti-viral agent,and combinations thereof.

Also provided is a kit including the device and a permeation enhancingagent. Example permeation enhancing agents are selected from the groupconsisting of dodecyl-2 (N,N-dimethylamino) propionate, bile salts,surfactants, fatty acids, glycerides, polyacrylic acid derivatives,chelating agents, nitric oxide donors, salicylates, chitosan, zonaoccludens toxins, sodium cholate, sodium deoxycholate, sodiumglycodeoxycholate, sodium taurocholate, sodium glycocholate,N-lauryl-b-maltopyranoside, and combinations thereof. Examplesurfactants include oleic acid, sodium dodecyl sulfate, sodium laurylsulfate, Polysorbate 80, lauryl esters, and combinations thereof.

In a second set of representative embodiments, there is provided amethod for manufacturing a rapid release delivery device for deliveringa therapeutic agent to a tissue, the method comprising: forming a firstmixture with a plurality of particles, the particles containing atherapeutic agent and having a coating around the therapeutic agent, thecoating including chitosan; adding chitosan, a hydration promoter, aparticle adhesion inhibitor, a particle aggregation inhibitor orcombinations thereof to the first mixture, to form a second mixture;freezing the second mixture in a bath containing an aqueous alcoholicsolution at a temperature above the freezing temperature of the aqueousalcoholic solution and at most −40° C., to form a frozen layerprecursor; drying the frozen layer precursor, to form a porous patchwith particles embedded within a polymeric matrix of the patch; andsterilizing the patch.

The bath may further contain dry ice. The alcohol of the aqueousalcoholic solution may be ethanol. The aqueous alcoholic solution may befrom about 90 wt % ethanol to about 99 wt % ethanol. A free quantity ofthe therapeutic agent may be embedded directly in the matrix, and nototherwise coated with chitosan, wherein the free quantity of thetherapeutic agent constitutes between 20-80% of a total quantity oftherapeutic agent in the device. The patch may include first and secondopposed surfaces and the first surface may be configured to be appliedto the tissue, the method further comprising adhering a backing layer tothe second surface of the patch, wherein the backing layer preventssignificant loss of payload components in the patch from diffusionthrough the second surface, and optionally protects the patch from anenvironment. The drying may be under vacuum. The sterilizing may includegamma ray irradiation.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Patent and Trademark Officeupon request and payment of necessary fee.

The foregoing features of embodiments will be more readily understood byreference to the following detailed description, taken with reference tothe accompanying drawings, in which:

FIG. 1A is a schematic illustration of an example patch containingparticles within a layer and a backing layer impermeable to significantpassage of particles or agent. The patch is to be applied to tissueaccording to embodiments of the present invention. FIG. 1B is aphotograph showing a top view of an example patch according toembodiments of the present invention. FIG. 1C is a photograph showing aperspective view of an example patch within a tumor cavity according toembodiments of the present invention.

FIG. 2 schematically illustrates the placement of a patch within a tumorcavity immediately following tumor resection according to embodiments ofthe present invention.

FIG. 3 is an image of an abdominal cavity with a patch topically placedupon affected tissue within the abdominal cavity to treat cancerouscells according to embodiments of the present invention.

FIG. 4 is a bar graph showing the results of a vertical diffusionexperiment which was conducted to observe the release profile of oneembodiment of the present invention.

FIGS. 5A, 5B, and 5C are photomicrographs showing the results from an exvivo experiment conducted on porcine stomach tissue.

FIG. 6 is a photomicrograph showing the results from an ex vivoexperiment conducted on porcine stomach tissue.

FIG. 7 is a photomicrograph showing the results from an ex vivoexperiment conducted on porcine stomach tissue.

FIG. 8 is an image of the matrix of an example patch overlaid with abrightened depiction of particles embedded within the matrix which arereleased upon application of the patch to tissue according toembodiments of the present invention.

FIGS. 9A, 9B, and 9C are graphs showing that agent(s) included within apatch, according to embodiments of the present invention, are notmodified when incorporated into the patch or when the patch issterilized. FIG. 9A is a graph showing a high-performance liquidchromatography (HPLC) chromatogram of a cisplatin standard. FIG. 9B is agraph showing an HPLC chromatogram of a patch, which illustrates thatthe cisplatin was not modified. FIG. 9C is a graph showing an HPLCchromatogram of a patch which underwent gamma sterilization, and furthershows that cisplatin was not modified.

FIG. 10 shows a comparison of particle release and permeation in thepresence and absence of propylene glycol

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires:

“Patch” refers to a device, mesh, wafer, matrix, sponge or similar likeproduct which contains elements incorporated therein to be releasedtherefrom.

“Permeation” is the ability to pass through or penetrate underlyingtissue upon which a patch has been topically applied.

“Biocompatible” refers to the ability of a biomaterial to perform itsdesired function with respect to a medical therapy, without elicitingany significant undesirable local or systemic effects in the recipientor beneficiary of that therapy, but generating the most appropriatebeneficial cellular or tissue response in that specific situation, andoptimizing the clinically relevant performance of that therapy.

“Biodegradable” refers to a property of a material rendering it capableof being broken down especially into innocuous products by the action ofliving organisms.

“Particles” refer to small objects having an average diameter of atleast 60 nm to at most 2000 nm.

“Adhesion inhibitor” refers to an additive that lowers the attractiveforces between a patch and particles embedded therein. As a result, theparticles can move through the patch at a faster rate than in theabsence of the adhesion inhibitor.

“Aggregation inhibitor” refers to an additive that lowers the tendencyof particles embedded in a patch to aggregate when the solution whichforms the patch is subjected to freeze drying. As a result, theparticles are less likely to suffer from damage or destruction when thefreezing takes place.

“Payload” refers to the therapeutic agents and other materials within apatch that are released from the patch upon application to tissue. Thepayload may include, for example, one or more components selected fromthe group consisting of particles, agents encapsulated within particles,freeform agents, adhesion inhibitors, aggregation inhibitors, hydrationpromoters, permeation enhancers, and combinations thereof.

“Polydispersity index” (PDI) or simply, “dispersity” is used herein torefer to a measure of the heterogeneity of sizes of particles in amixture. PDI measures the size dispersity of nanoparticles.

“Zeta potential” (ZP) is used herein to refer to the overall charge thatnanoparticles acquire in a particular medium and can be measured on aZetasizer Nano instrument.

A “particle diameter” is the length of the longest axis between twopoints on the surface of the particle.

“HPMC” refers to hydroxypropyl methylcellulose, also known ashypromellose.

“Tissue” in the context of embodiments of the present invention refersto organ, epithelial, mucosal, or other tissue which exists withinregions such as the abdomen, pelvis, intraperitoneal cavity, and/orother intraperitoneal surfaces.

“Surgical cavity” refers to the cavity, opening, site or tissue surfacethat results from the surgical resection of tissue.

“Rapid”, “rapid release”, or “rapid delivery” in reference to releasefrom the patch refers to the release of between 20% and 100% of thepatch's payload within approximately 20 minutes.

“Kilo counts per second” or “Kcps”, mean count rate (in thousands ofcounts per second). For example, the threshold may be set such that whenthe count rate of the sample is lower than 100, the measurement shouldbe aborted, meaning the concentration of the sample is too low formeasurements. A sample with suitable Kcps can be considered a stablesample with an acceptable concentration for measurement.

Unless otherwise specified, the term “wt %” refers to the amount of acomponent of a system for delivery of a therapeutic agent, as expressedin percentage by weight.

Unless otherwise specified, the “molar mass” of a polymer is intended tomean the number average molar mass of the polymer molecules.

“Impermeable” refers to a layer not allowing a given substance to passthrough. For example, a layer may be impermeable to one or more chemicalcompounds, and/or to particles having a diameter equal to or larger thana certain threshold value. The term “substantially impermeable” appliesto instances where the layer allows the passage of minimal amounts ofthe substance, for example less than 1% or 2% of the total amount of thesubstance.

Intraoperative Rapid Release Patch

Embodiments of the present invention provide a device in the form of apatch which is topically applied following surgery to target andeliminate remaining tumor cells within the surgical cavity. Asillustrated in FIGS. 1A-1C and 2, the device is able to overcome thelimitations of IORT, HIPEC, systemic chemotherapy and standalone surgerydue to its ability to deliver and retain a high concentration of achemotherapeutic agent locally. The patch is placed in the bed (cavity)which is formed following resection of the tumor. The patch is able torestrict exposure of the tumor cavity to the systemic bloodstream due tochitosan's coagulant effect and rapidly release particles into thetissue which permeate and target remaining cancer cells. The device maybe applied as a simple topical administration, high in safety due to theuse of a small amount of highly targeted agent. The device may have anapplication time as low as a few minutes, which does not increase theduration of surgery since it can easily be applied while other tasks inthe operating room are being performed to prepare for closing theresected region. The device can be easily manufactured and distributedfor widespread commercial availability. In addition, embodiments of thepresent invention are able to provide higher efficacy than othertreatment options due to local targeting and retention.

Also as illustrated in FIGS. 1A-1C and as further illustrated in FIG. 3,the patch provides rapid delivery of one or more agents to the surgicalcavity, preventing the spread of cancerous cells, and offering a highdegree of agent retention to the applied tissue and to tumor cells. Thepatch is applied and topically adheres to the desired organ or tissue,for example the bed of the tumor surface within stomach, smallintestine, colon, pancreas, spleen, liver, rectum, uterus, ovaries, andperitoneal surface tissue, as exemplified in FIG. 3. The topicalplacement of the patch allows delivery of the patch's payload to theunderlying cells. The particles in the payload penetrate the tissue andrelease the agent or agents directly into the tissue. Multiple patchesmay also be used to treat cancer affecting a number of locations.

The novelty of this patch lies in part with its property of rapidtherapeutic agent release. Unlike other implantable patches whichprovide slow sustained agent release, the patch of the presentapplication has been primarily designed to allow for rapid agentrelease. The percentage of agent released in a rapid fashion can bemodulated depending on a desired preference, and the release from thepatch is able to range from a minimum of 20% release to a maximum of100% release within approximately 20 minutes or less. As such, thepayload of the patch is released up to approximately 20 minutesfollowing surgery, after which the patch is removed and disposed of.FIG. 4 is a bar graph showing the results of a vertical diffusionexperiment which was conducted to observe the release profile of examplepatches according to one embodiment of the present invention. Fivesamples were tested for this particular experiment. Vertical diffusionwas conducted on a collagen membrane to gauge the release profile of oneembodiment of the present invention. This embodiment included the agentcisplatin encapsulated within chitosan particles with a range in size ofapproximately 500 nm. The particles were released onto the collagen,after which they were allowed to diffuse into the underlying solution.As shown, between 92.40% and 96.84% of the particles and agent withinthe patch were released after 15 minutes, and between 94.84% and 99.11%of the particles and agent were released from the patch after 20minutes. This is one of a number of experiments which have confirmed therapid release properties of example patches according to embodiments ofthe present invention.

While implantable wafers are being developed that are intended for slowrelease of agents over several months, the patch of the presentapplication is rather intended for non-implantable, intraoperative usewhere rapid release of all embedded agent is required during the surgeryand its retention in the tumor bed is essential for its successfulapplication. In addition to uses in complete tumor resection surgery,the patch may be used for other intraoperative applications, for examplein the context of procedures known as cytoreductive surgery or debulkingwhere, due to complications, the tumor cannot completely be removed. Assuch, the surgery is frequently used only as a means of reducing tumorsize, leaving some tumor tissue behind. In these instances, the patchcan be easily applied to the remaining tumor since it can be fitted inhard to reach and operate regions by virtue of its pliability, its smallsize and its flexibility. The patch then can be removed when the woundis ready for closure.

As illustrated in FIG. 1A, a patch 10 includes a layer 12 having firstand second opposed surfaces and a backing layer 14 adjacent to one ofthe surfaces. Layer 12 contains at least one therapeutic agent and aporous, mucoadhesive polymeric matrix that is formed by freeze-drying acomposition including chitosan. Particles 16 are embedded within thematrix. As further illustrated in FIG. 8, the particles 16 are directlysurrounded by, and in contact with, the matrix. The particles 16 containthe therapeutic agent and have a coating around the therapeutic agent,the coating including chitosan so as to provide controlled release ofthe therapeutic agent from the particles. A quantity of the therapeuticagent may be embedded directly in the matrix as freeform agent, and nototherwise coated with chitosan. In representative examples, the freeformquantity of the therapeutic agent constitutes between 20-80% of a totalquantity of the therapeutic agent in the device. Backing layer 14 isimpermeable to, or at least substantially impermeable to, the passage ofone or more payload components such as the particles, therapeutic agent,or additives present in the patch. Examples of backing layer materialsinclude a non-woven polyester fabric with or without a polyacrylateadhesive and/or a clear acrylic film.

Representative examples of matrix materials and particles that may formlayer 12 are provided in U.S. Patent Appl. Publ. No. 2017/0239189, wherechitosan particles embedded in a chitosan-based matrix are disclosed.This prior application is hereby incorporated herein by reference in itsentirety; however, the definitions provided above in paragraph 25 shallprevail over any contrary definitions in the prior application. Chitosanis a deacetylated derivative of chitin, the second most abundantpolysaccharide, and has a large density of reactive groups and a widerange of molecular weights. Chitosan is considered useful as abioadhesive material because of its ability to form non-covalent bondswith biological tissues, mainly epithelia and mucous membranes.Bioadhesions formed using natural polymers have unique properties as acarrier because they can prolong residence time and, therefore, increasethe absorbance of loaded drugs. Chitosan is a bioabsorbable,biocompatible, biodegradable, anti-bacterial and non-toxic polymer.

In addition, chitosan has different functional groups that can bemodified. Because of its unique physicochemical properties, chitosan hasgreat potential in a range of biomedical applications. Chitosan can beused as a delivery mechanism because of its bio-adhesiveness as well asits established ability to act as an absorption and permeation enhancer.The barrier in mucosa or epithelium can easily be disrupted by chitosanparticles, enhancing permeability through mucosa. Chitosan has beenfound to be an ideal material for enabling efficacy and functionality ofthe patch. In the course of experiments, following surgical resection oftumors, a chitosan-based patch was applied within the surgical cavity.Only treatment with the chitosan-based patch resulted in essentially norecurrence or metastasis of cancer cells. Other patches, such as patchesmade of purely HPMC, pectin, alginate did not yield these same effectsfor unknown reasons. Chitosan is a blood coagulant, likely due tochitosan's positive charge attracting and retaining negatively-chargedred blood cells upon exposure to blood, which results in coagulation[15, 16]. This coagulation, in combination with other unknown factors,may prevent the spread of free cancer cells within the bloodstream andbody. In addition, chitosan loosens the tight cell junctions withintissue to increase permeation and passage of agents within tissue. Thiseffect may, in part, prevent the spread of cancerous cells within localand systemic tissue due to cancerous cells becoming attracted towardsthe patch because of the cells' more acidic properties or other unknownfactors. In permeation studies conducted with a number of patchmaterials, similar permeation of particles was noted in chitosan-basedpatches as well as non-chitosan-based patches, so additional permeation,in and of itself, does not result in this higher efficacy.

Published application US 2017/0239189 A1 also states, in paragraph[0095], as follows: “It has been found that better results are providedif the particles are made from pure chitosan, a material characterizedby not being a salt, that is, with its amine groups unprotonated, andhaving a degree of deacetylation of at least 70%. In particular, theparticles are characterized by larger diameters than traditionalparticles. In some embodiments, the average diameter of the purechitosan particles may range from about 200 to about 2000 nanometers. Inother embodiments, the average diameter ranges from about 500 to about2000 nanometers, and in additional embodiments from 500 to 1000 nm.”

The most widely developed particle manufacturing methods are ionotropicgelation and self-assembling polyelectrolytes. These methods offer manyadvantages, such as a simple and mild preparation method without the useof organic solvent or high shear force. These methods are applicable tobroad categories of agents including macromolecules which are notoriousas labile agents. Usually, the factors found that affects particleformation, including particle size and surface charge, are molecularweight and degree of deacetylation of chitosan. The particles may betailored to be stable in a variety of environments.

The ionotropic gelation method is commonly used to prepare chitosanparticles. This method is based on electrostatic interaction; atphysiologic pH, the primary amine groups of chitosan are protonated, andtherefore chitosan is positive-charged. The positive charge is used toform particles in solution via cross-linking with polyanions(stabilizer) such as sodium tripolyphosphate (STPP), to efficientlyencapsulate the drug via electrostatic interaction, and to promotecellular internalization of drug-containing chitosan particles.Polyanionic stabilizers may function as cross-linkers to form theparticles by acting as a negative counter-ion to the positively chargedamine groups on chitosan. This electrostatic interaction forms ionicbonds that support the structure of the particles. Also, the presence ofsodium as positive counter-ion may render STPP a more effectivecross-linker than other tripolyphosphate (TPP) salts.

Several advantages of this simple and mild method include the use ofaqueous solutions, the preparation of particles with a small size, themanipulation of particle size by the variation in pH values, and thepossibility of encapsulation of drug during particle formation.Structural changes can be introduced by ionic strength variations, likepresence of KCl at low and moderate concentrations emphasize swellingand weakness of chitosan-STPP ionic interactions.

The particles can permeate tissue to deliver encapsulated agents. Theparticle size is dependent on the pH of the aqueous solution from whichthey are prepared and the weight ratio of chitosan to STPP, and the sizeof the particles influences the drug release rates. Other parametersaffect the particles including the chitosan:stabilizer (such as STPP)ratio in aqueous solution during the synthesis process, as an increasein the amount of stabilizer leads to a higher degree of chitosancross-linking and a decrease in the particle dimensions. Accordingly,the size of the particles can be modulated, allowing the use of specificparticle size ranges tailored to the tissue for which the particles arechosen.

Once the patch is prepared, the patch is subjected to a sterilizationprocess that ensures that the final product meets the sterilityrequirements of surgery applications while not appreciably degrading thecomponents or performance of the patch. In particular, care should betaken that the sterilizing process does not significantly affect thestructure and efficacy of the therapeutic agent contained in the patch.Gamma ray irradiation, which uses radiation emitted from radioactiveisotopes such as Cobalt 60 to kill microorganisms, has been found toeffectively sterilize patches while leaving chemotherapeutic agentsessentially unaffected.

The permeability of the particles and the agent is one of the importantfactors to the efficacy of the patch. This attribute is designed andoptimized for intra-operation chemotherapy. The agent and particlesshould permeate deep enough to effectively destroy the micrometastaticcells in the tissue surrounding the resected tumor, but not so deep asto be removed by the bloodstream. An example is shown in FIGS. 5A-5C,where freshly harvested porcine tissue was used to gauge permeationability. A pig was sacrificed and patches were applied to its excisedstomach tissue within a very short time. Patches contained the greenfluorescent dye Fluorescein isothiocyanate (FITC) encapsulated withinthe particles with an average size of approximately 450 nm. Patches weresynthesized according to a freeze drying method and particles weresynthesized using the ionic gelation technique. The chitosan particlesthemselves were conjugated to the red fluorescent dye cyanine 5 (Cy5).Patches containing these two dyes were tested and the images in FIGS.5A-5C show the results following treatment with these patches. Alltissue surfaces were washed following treatment to remove any remainingfluorescence on the tissue surface. FIG. 5A is a 4× zoom overlay wherethe scale bar has a length of 1000 μm. The microscope used was a LifeTechnologies EVOS model where fluorescence was UV induced. As shown, theparticles permeated into the tissue and the encapsulated agent permeateddeep into tissue. FIG. 5B is a 10× zoom picture of the porcine stomachtissue. The scale bar is 400 μm long and the fluorescence patternsreveal deep permeation into the tissue. While difficult to see, the redCy5 dye has permeated all the way to the upper right of the image. FIG.5C is a 40× zoom of the stomach tissue. The scale bar is 100 μm. Thiscloser image better visualizes the particles within the tissue. Asshown, the red Cy5 particles can be observed scattered within thetissue.

FIG. 6 shows the results of a similar experiment conducted on porcinesmall intestine. The image (scale bar 400 μm) shows deep permeationwithin the small intestine tissue of the (red/orange) particles andencapsulated agent (green). The tissue surface was washed followingtreatment to remove any remaining fluorescence on the tissue surface.

FIG. 7 shows another example of the patch with particles of differentsizes included that resulted in permeation to different tissue depths. Asimilar experiment was conducted on porcine spleen tissue with particleshaving an average diameter of 600 nm. The image shows permeation of theagent labeled with FITC within the tissue of the spleen. The tissuesurface was washed following treatment to remove any remainingfluorescence on the tissue surface.

In some embodiments, the patch also contains an additive including atleast one of the following: (1) a particle aggregation inhibitor, (2) aparticle adhesion inhibitor, and/or (3) an agent to promote hydration ofthe patch to facilitate particle/agent release. Example aggregationinhibitors, adhesion inhibitors, and aggregation promoters are alsodisclosed in the above-cited U.S. Patent Appl. Publ. No. 2017/0239189.The particles were found to inherently release poorly from the patch. Inorder to release the particles at a satisfactory rate and amount, atleast one of these additives should be included within the compositionof the patch.

The addition of a hydration promoter (propylene glycol) wasexperimentally tested, and was found to significantly increase releaseand permeation of the payload within the patch. Without wishing to bebound to any particular theory, the hydration promoter may increasemoisture absorption by the delivery device, enabling the rapid releaseand permeation of the particles from the patch. The hydration promotermay also improve uniformity and durability by acting as a cryoprotectantduring the manufacturing process of the delivery device. Again withoutbeing bound to any particular theory, the hydration promoter may act asa “spacer” between ice crystals and patch polymer molecules, to ensure auniform freezing pattern. The resulting structure is more flexible,uniform, and durable than in the absence of the hydration promoter.

To illustrate the improvement in performance imparted by hydrationpromoters, patches including a chitosan polymer and chitosan particleswere manufactured with and without propylene glycol (PG) in the patchbody. The particle release and permeation of the patches was measuredfor both types of patch, and the experiment was run in triplicate. Asreported in the chart of FIG. 10, the average percentage of permeationin the presence of propylene glycol ((+)PG) was 94% with a standarddeviation of about 3%, which dropped to 43% with a standard deviation of27% in the absence of propylene glycol ((−)PG). The percentage ofrelease in the presence of propylene glycol was 95% with a standarddeviation of about 3%, as opposed to 21% with a standard deviation of41% without PG. Clearly, patches with PG performed markedly better thanthose without, and release and permeation numbers were more reproducibleas shown by the smaller standard deviations.

In some embodiments, there are provided patches whose functionality isimproved by the addition of an adhesion inhibitor. Without wishing to bebound to any particular theory, when the patch and particles are made ofmaterials bearing polar or ionically charged moieties, such as chitosan,the mobility of the particles suffers. In the instance of chitosan, theinteractions between acetyl and amine moieties of the polymer may causethe particles to adhere to the patch body and inhibit their release. Theinclusion of an adhesion inhibitor may mitigate adhesion of the patchwith the particles. Again without being bound to any particular theory,the adhesion inhibitor may act as a “spacer” between the chitosan of theparticles and the chitosan in the body of the patch, releasing theparticles and allowing for improved drug release profiles.

Representative example adhesion inhibitors include non-ionic polymerssuch as hydroxypropyl methylcellulose (HPMC). Depending on theapplication, the molar mass of the non-ionic polymer may be from about 1kDa to about 200,000 kDa, while its viscosity may vary from about 10 cpsto 100,000 cps. In representative embodiments, the molar mass of thenon-ionic polymer is from about 10 kDa to 30 kDa, and its viscosity fromabout 10 cps to about 100 cps. Depending on the application, the amountof adhesion inhibitor may be from about 0.1 wt % to about 99 wt % oftotal patch weight. In some embodiments, the amount of adhesioninhibitor is from about 0.1 wt % to about 25 wt %.

In some embodiments, the functionality of the patch is improved by theaddition of an aggregation inhibitor. Processes for manufacturing thedelivery devices include freezing steps during which ice crystals mayform within the patch. Such crystals can force the particles into eachother, creating particle aggregates where the particles are damaged ordestroyed. Without wishing to be bound to any particular theory,aggregation inhibitors may exert a cryoprotectant action by formingcrystal microstructures which prevent aggregation of the particles.Sugars and sugar derivatives provide exemplary types of aggregationinhibitors, including monosaccharides, disaccharides, sugar alcohols,chlorinated monosaccharides, and chlorinated disaccharides such assucralose. Depending on the application, the amount of aggregationinhibitor in the patch may be in the range from about 0.1 to about 50 wt%. In some embodiments, the amount of aggregation inhibitor is fromabout 1 to about 10 wt %.

The patch is sterilized prior to application to a surgical cavity, forexample after the patch is manufactured and before packaging. In someembodiments, gamma sterilization is employed to sterilize the patch.FIGS. 9A-9C show HPLC chromatograms at various stages of productsynthesis. The HPLC apparatus was an Agilent 1100 Series HPLC using awater/methanol/sodium lauryl sulfate solvent mixture adjusted to pH 2.5with trifluoromethanesulfonic acid. FIG. 9A is an HPLC chromatogram of acisplatin standard. FIG. 9B is an HPLC chromatogram of a cisplatinsample taken from a patch that was dissolved in a solution, whichillustrates that the cisplatin was not modified while in the patch. FIG.9C is an HPLC chromatogram of cisplatin extracted from a patch whichunderwent gamma ray sterilization for 25 minutes, and further shows thatcisplatin was not modified. Similar experiments were conducted usingoxaliplatin and 5-fluorouracil. This experiment proves that the patchesare able to be manufactured and sterilized while maintaining theintegrity of the agent(s) included within.

In some embodiments, the patch is formed with one side exposed forcontact with the appropriate tissue. Particles containing the agent oragents will be released from this side upon contact with the appropriatetissue. As illustrated in FIG. 8 the particles (round) are held withinthe body of the patch. The body of the patch is the web-like material,which is primarily comprised of chitosan. In some embodiments, the otherside facing the external cavity may be adjacent to a backing layer 14,for instance a film, coating, or impermeable membrane to preventsignificant loss of one or more payload components from the patch intothe tissue/cavity on the opposite side from the desired tissue. Thisbacking layer 14 may also prevent contamination of the patch with fluidsor other matter that may be present.

The patch makes use of well-known chemotherapeutics in some embodimentsas well as commercially available excipients, additionally minimizingthe costs associated with its manufacture. The simple manufacturingprocess, relatively low overall costs, and easy method of administrationserve as improvements over all existing intraoperative treatmentmethods, and will promote a widespread uptake and utilization of thepresent invention.

In some embodiments, the patch contains a combination of two or morechemotherapeutics to be delivered to a surgical cavity within theabdomen, pelvis and/or intraperitoneal region, where each of thechemotherapeutics is present at some ratio of freeform chemotherapeuticto particle-encapsulated chemotherapeutic. In some embodiments where twoor more chemotherapeutics are included, one chemotherapeutic may beencapsulated within particles while the other remains freeform. Forexample, if cisplatin and oxaliplatin are desired chemotherapeutics forinclusion within the patch, one such chemotherapeutic (cisplatin) may beincluded in particle form while oxaliplatin may be included in freeform.

In other embodiments where two or more chemotherapeutics are included,one chemotherapeutic may be encapsulated within particles while theother exists both in freeform and within particles. For example, ifcisplatin and oxaliplatin are desired chemotherapeutics for inclusionwithin the patch, one such chemotherapeutic (cisplatin) may be includedin particle form while oxaliplatin may be included both in freeform andencapsulated within particles. In additional embodiments where two ormore chemotherapeutics are included, two or more of thechemotherapeutics may be included both within particles and both infreeform. For example, if cisplatin and oxaliplatin are desiredchemotherapeutics for inclusion within the patch, both cisplatin andoxaliplatin may exist encapsulated both within particles andadditionally in freeform at a desired ratio within the final patchproduct.

In some embodiments, at least one agent included within the patch is ananti-infective agent, which may be included in freeform, encapsulatedwithin particles, or a combination thereof. In some embodiments, atleast one agent included within the patch is an anti-bacterial oranti-viral agent, which may be included in freeform, encapsulated withinparticles, or a combination thereof. In some embodiments, the majorityof particles range in diameter from 60 nanometers to 2 microns. In a setof preferred embodiments, the particles have an average diameter between100 nm and 1000 nm. More preferably, the particles have an averagediameter of 200-500 nm or of 100 to 400 nm.

In some embodiments, at least one patch is included as a component of akit for the treatment of abdominal, pelvic and/or intraperitonealdiseases which are accessible via surgery. This kit may includematerials that are required for proper administration of the patch aswell as proper and safe disposal of the patch after application andcleaning of the treated area. For example, FOLFOX (5-FU, leucovorin, andoxaliplatin) or CapeOx (capecitabine and oxaliplatin) regimens areknown, common agents for the treatment of traditional colon cancer.These chemotherapeutics can be utilized in a safe manner to topicallytreat colon tumors which may have metastasized within theabdomen/pelvis. However, extensive precautions must be taken to ensurethat (1) proper handling procedures are followed during treatment, (2)time to prepare and administer the patch is reduced to minimize the timewithin which the patient's abdomen/pelvis remain exposed, and (3) ensurethat contact is minimized between these agents and both the patient andpersonnel applying the patch. Items that may then be included in the kitfor the purpose of safety can include forceps or other tools for theplacement of the patch, disposable packaging for any remaining portionof the patch after application and other safety components.

In addition, a permeation enhancing agent may be included within thekit. The permeation enhancer may be applied briefly prior to applicationof the patch. Example classes of permeation enhancing agents includebile salts, fatty acids, glycerides, polyacrylic acid derivatives,chelating agents, nitric oxide donors, salicylates, chitosan, and zonaoccludens toxins, and specific example permeation enhancers includedodecyl-2 (N,N-dimethylamino) propionate, sodium cholate sodiumdeoxycholate, sodium glycodeoxycholate, sodium taurocholate, sodiumglycocholate, and N-lauryl-b-maltopyranoside. Certain surfactants mayserve as permeation enhancing agents, for instance Poloxymer 407,Poloxymer 188, Tween 20, Span 20, oleic acid, sodium dodecyl sulfate,sodium lauryl sulfate, Polysorbate 80, and lauryl esters.

The embodiments of the described above are intended to be merelyexemplary; numerous variations and modifications will be apparent tothose skilled in the art. All such variations and modifications areintended to be within the scope of the present invention as defined inthe appended claims.

REFERENCES

-   [1] “What Is Metastatic Cancer?” American Cancer Society. N.p., n.d.    Web. 25 Apr. 2017.-   [2] “Metastatic Cancer.” National Cancer Institute. N.p., n.d. Web.    25 Apr. 2017.-   [3] Hanna Dillekås, Monica Transeth, Martin Pilskog et al.    “Differences in metastatic patterns in relation to time between    primary surgery and first relapse from breast cancer suggest    synchronized growth of dormant micrometastases”. Breast Cancer Res    Treat. 2014; 146(3): 627-636.-   [4] Tufts Medical Center “Cytoreductive Surgery with Hyperthermic    Intraperitoneal Chemotherapy (HIPEC).”-   [5] Zhang W, Zhong D, Liu Q et al. “Effect of chitosan and    carboxymethyl chitosan on fibrinogen structure and blood    coagulation.” J Biomater Sci Polym Ed. 2013; 24(13):1549-63. doi:    10.1080/09205063.2013.777229.-   [6] Elena Sperk, Daniela Astor, Anke Keller et al. “A cohort    analysis to identify eligible patients for intraoperative    radiotherapy (TORT) of early breast cancer” Radiation Oncology    20149:154 DOI: 10.1186/1748-717X-9-154.-   [7] Tulunay et al, Pilot study of intraoperative chemotherapy with    cisplatin and 5-Fluorouracil in patients with advances squamous cell    carcinoma of the head and neck-2006 in Wiley InterScience, DOI:    10.1002/hed. 20521.-   [8] Harless et al, Revisiting perioperative chemotherapy: the    critical importance of targeting residual cancer prior to wound    healing, Published: 22 Apr. 2009, BMC Cancer 2009, 9:118 doi:    10.1186/1471-2407-9-118.-   [9] West Virginia University. “ORT Intraoperative Radiation Therapy”    medicine Health Report.-   [10] Cancer Treatment Centers of America. “IORT Medical Animation”.    CTCA Cancer Videos.” CancerCenter.com-   [11] New Radiant Technology S.p.A. “Novac 7, The First mobile    electron linear accelerator for IORT”    http://sennewald.de/wp-content/uploads/novac7.pdf-   [12] Tufts Medical Center “Cytoreductive Surgery with Hyperthermic    Intraperitoneal Chemotherapy (HIPEC)”-   [13] Cancer Treatment Centers of America. “Hyperthermic    intraperitoneal chemotherapy (HIPEC)”. CancerCenter.com-   [14] Northwestern University. “When Fighting Cancer Isn't Worth It”,    Mary Mulcahy, Jan. 4, 2013.-   [15] Tianhong Dai et al, Chitosan preparations for wounds and burns:    antimicrobial and wound-healing effects, Expert Rev Anti Infect    Therapy. 2011 July; 9(7): 857-879.-   [16] Biodegradability of Chitin and Chitosan Containing Films in    Soil Environment; Journal of Environmental Polymer Degradation Vol.    3 No. 1 1995. Makarios-Laham, Tung-Ching Lee.

What is claimed is:
 1. A device for rapid delivery of a therapeuticagent to a surgical cavity, the device comprising: a porous,mucoadhesive, freeze-dried polymeric matrix having first and secondopposed surfaces, the matrix formed by a composition comprisingchitosan, and a plurality of particles, having an average diameterbetween 500 nm and 2000 nm, embedded within the matrix so as to bedirectly surrounded by, and in contact with, the matrix, the particlescontaining the therapeutic agent and having a coating around thetherapeutic agent, the coating comprising chitosan so as to providecontrolled release of the therapeutic agent from the particles throughthe first opposed surface of the matrix; wherein: the first surface ofthe matrix is configured to be applied to the surgical cavity; thedevice is configured to provide release of the particles through thefirst surface; the device is sterilized; and the device provides releaseof approximately 20% to 100% of the therapeutic agent within 20 minutesof application to the surgical cavity.
 2. A device according to claim 1,the composition further comprising one or more additives selected fromthe group consisting of a hydration promotor, a particle adhesioninhibitor comprising hydroxyproplymethylcellulose (HPMC), a particleaggregation inhibitor, and combinations thereof.
 3. A device accordingto claim 2, wherein the hydration promoter is selected from the groupconsisting of ethylene glycol, propylene glycol, beta-propylene glycol,glycerol and combinations thereof.
 4. A device according to claim 2,wherein, when present, the particle adhesion inhibitor and, thehydration promotor, and the particle aggregation inhibitor are compoundsmutually distinct from one another and present in amounts sufficient toachieve the controlled release of the particles without preventingformation of the freeze-dried matrix.
 5. A device according to claim 2,wherein the particle aggregation inhibitor is selected from the groupconsisting of monosaccharides, disaccharides, sugar alcohols,chlorinated monosaccharides, chlorinated disaccharides, and combinationsthereof.
 6. A device according to claim 1, wherein the particles furtherinclude sodium tripolyphosphate.
 7. A device according to claim 1,further comprising a free quantity of the therapeutic agent, embeddeddirectly in the matrix, and not otherwise coated with chitosan, whereinthe free quantity of the therapeutic agent constitutes between 20-80% ofa total quantity of therapeutic agent in the device.
 8. A deviceaccording to claim 1, further comprising a backing layer disposed on thesecond surface, wherein the backing layer prevents significant loss ofpayload components in the device from diffusion through the secondsurface, and optionally protects the device from an environment.
 9. Adevice according to claim 8, wherein the backing layer includes amaterial selected from the group consisting of a polyacrylate adhesive,a non-woven polyester fabric backing, and combinations thereof.
 10. Adevice according to claim 1, wherein the therapeutic agent is achemotherapeutic pharmaceutical.
 11. A device according to claim 10,wherein the chemotherapeutic is selected from the group consisting ofplatinum-based chemotherapeutics, 5-flurouracil, and combinationsthereof.
 12. A device according to claim 1, wherein the therapeuticagent is an agent selected from the group consisting of anti-infective,anti-bacterial, or anti-viral agent, and combinations thereof.
 13. A kitcomprising the device according to claim 1 and a permeation enhancingagent selected from the group consisting ofdodecyl-2-(N,N-dimethylamino) propionate, bile salts, surfactants, fattyacids, glycerides, polyacrylic acid derivatives, chelating agents,nitric oxide donors, salicylates, chitosan, zona occludens toxins, andcombinations thereof.
 14. A kit according to claim 13, wherein thepermeation enhancing agent is selected from the group consisting ofsodium cholate, sodium deoxycholate, sodium glycodeoxycholate, sodiumtaurocholate, sodium glycocholate, N-lauryl-b-maltopyranoside, andcombinations thereof.
 15. A kit according to claim 13, wherein thepermeation enhancing agent is a surfactant selected from the groupconsisting of oleic acid, sodium dodecyl sulfate, sodium lauryl sulfate,polysorbate 80, lauryl esters, and combinations thereof.
 16. A methodfor manufacturing a device according to claim 1, the method comprising:forming a first mixture with a plurality of particles having an averagediameter between 500 nm and 2000 nm, the particles containing atherapeutic agent and having a coating around the therapeutic agent, thecoating including chitosan; adding chitosan to the first mixture, toform a second mixture; freezing the second mixture in a bath containingan aqueous alcoholic solution at a temperature above the freezingtemperature of the aqueous alcoholic solution and at most −40° C., toform a frozen layer precursor; drying the frozen layer precursor, toform a porous patch with particles embedded within a polymeric matrix ofthe patch; and sterilizing the patch.
 17. A method according to claim16, wherein the bath further contains dry ice.
 18. A method according toclaim 16, wherein the alcohol of the aqueous alcoholic solution isethanol.
 19. A method according to claim 16, wherein the aqueousalcoholic solution is from about 90 wt % ethanol to about 99 wt %ethanol.
 20. A method according to claim 16, wherein a free quantity ofthe therapeutic agent is embedded directly in the matrix, and nototherwise coated with chitosan, wherein the free quantity of thetherapeutic agent constitutes between 20-80% of a total quantity oftherapeutic agent in the device.
 21. A method according to claim 16,wherein the patch includes first and second opposed surfaces and thefirst surface is configured to be applied to the tissue, the methodfurther comprising adhering a backing layer to the second surface of thepatch, wherein the backing layer prevents significant loss of payloadcomponents in the patch from diffusion through the second surface, andoptionally protects the patch from an environment.
 22. A methodaccording to claim 16, wherein the drying is under vacuum.
 23. A methodaccording to claim 16, wherein the sterilizing includes gamma rayirradiation.